Catalytic oligomerization of olefinic monomers

摘要

A catalyst precursor composition comprising: a source of chromium, molybdenum or tungsten; a first ligand having the general formula (R1)(R2P—X—P(R3)(R4); and a second ligand having the general formula (R1′)(R2′)P—X′—P(R3′)(R4′). The present invention also relates to a catalyst system comprising the catalyst precursor composition of the present invention and a cocatalyst. The present invention further relates to a process for the trimerization and tetramerization of olefinic monomers, particularly the trimerization and tetramerization of ethylene to 1-hexene and 1-octene, wherein the process comprises contacting at least one olefinic monomer with the catalyst system of the present invention.